The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 26, 1989
Filed:
Mar. 28, 1989
Horng-Jye Sun, Fremont, CA (US);
Teledyne MEC, Mountain View, CA (US);
Abstract
A MMIC variable att4enuator uses depletion mode Schottky gate FETS as variable conductance devices in a '.pi.' configuration to vary attenuation as a function of a DC control voltage. Attenuation is flat within .+-.1 dB, VSWR is .ltoreq.2:1 throughout the operating frequency and control voltage range, and about 12 dB variable attenuation is provided. The '.pi.' is formed by FETs in shunt to ground between attenuator input and output, and by a FET in series between input and output. Resistors and an inductor connected in parallel with the series FET extend attenuator bandwidth to 20 GHZ and improve attenuation linearity versus control voltage. A resistor in series with each shunt FET also improves linearity. The typically 0 to +3 VDC control voltage is applied to the FET gates and drain/source leads permitting attenuation control with a single control voltage. FR power capability is increased without degrading RF performance by using multi-gate FETs wherein the ratio of gate width to number of gates is maintained substantially constant compared to a single-gate FET. Series-connected FETs further increase attenuator RF power capability. Operating from 2-20 GHz, embodiments using a single control voltage handle about 30 mW RF input power and use single-gate and dual-gate FETs, and handle about 250 mW RF input power and use triple-gate FETs. A third embodiment, operating from DC-20 GHz and handling about 500 mW RF input power, employs dual-gate FETs throughout and requires two complementary control voltages.